Rami Arieli: "The Laser Adventure"

Rami Arieli: "The Laser Adventure" Chapter 6, Ion Gas Lasers, page 1a

Power Output from Argon Laser
When considering the power output of the Argon laser, it is important to state if the power output is at all the laser lines together, or at a specific wavelength.
Some applications require specific wavelength which can be chosen by a grating or prism at the end of the optical cavity, as we shall see in chapter 8.2.1.
We shall see (in chapter 9.4.9 that one of the attractive applications of the Argon Ion laser is in producing visual effect for art and entertainment.
The ionized gas lasers are the only visible lasers that produce many colors with comparatively high power (up to a few Watts).

Argon (Ar⁺) laser efficiency
We see from the diagram in figure 6.4 that the lasing energy levels belong to the Argon ion, so the atoms of the gas inside the tube need to be ionized first.

As seen in the diagram, the ground state of the laser is at about 16 [eV] above the ground state of the neutral Argon atom. This is a large amount of energy that must be supplied to the laser, but is not used for creating laser radiation. This "wasted" energy is one of the reasons for the very low efficiency of the Argon laser (0.1%).